Astronomers Find 7,500-Light-Year Carina Cloud Forging Young Stars

Q: How did a “ghostly” cloud in the Carina Nebula turn out to hide about 70 newborn stars instead of a dead star’s remains?

It turned out to be a nursery, not a graveyard, because newer observations could see through the cloud’s deceptive appearance. What looked like a faint, isolated remnant of a dead star was revealed by NASA’s Chandra X-ray Observatory and the James Webb Space Telescope to be a dense cometary globule in the Carina Nebula, still actively forming stars. Webb’s infrared vision penetrated the dust and uncovered a compact embedded cluster of about 70 young stars, including a rare massive O-type star about 19 times the Sun’s mass. Chandra’s X-ray data helped identify the hot, energetic young stars and map conditions inside the cloud. Together, the two telescopes showed both the structure of the gas and dust and the hidden stellar population within it. The cloud’s “ghostly” shape also helped cause the confusion. It has been sculpted by harsh ultraviolet radiation and stellar winds from Eta Carinae and other nearby massive stars, which are eroding the outer layers and stretching the cloud into a comet-like form. That made it resemble debris or a stellar remnant, even though its dense core is still producing stars. So the object was misread because it looked wispy and isolated from the outside. Multiwavelength observations showed that beneath that stripped, glowing exterior is an active, very young star-forming region—sometimes called the “Treasure Chest”—where creation and destruction are happening at the same time.

Q: Is Eta Carinae helping create stars in the Treasure Chest cloud, or destroying the nursery that feeds them?

Eta Carinae is doing both, but the evidence suggests it is more directly eroding the Treasure Chest cloud than creating its stars. Observations from NASA’s Chandra X-ray Observatory and the James Webb Space Telescope show that the Treasure Chest is an active star-forming region, not the remains of a dead star. Webb found an embedded cluster of about 70 young stars inside the cloud, including a rare massive O-type star, which means star formation is already underway in the dense core. At the same time, Eta Carinae’s intense ultraviolet radiation and stellar winds are stripping gas and dust from the cloud and sculpting it into a cometary globule, with a dense head and trailing tail. Scientists describe this as stellar feedback: the same energy that shapes the cloud is also eating away at the raw material needed for future star formation. The likely picture is that the stars in the Treasure Chest formed in a larger cloud, and Eta Carinae and other nearby hot stars then blasted away the looser outer layers, leaving behind the denser pocket now seen as the Treasure Chest. That means Eta Carinae may have helped compress or expose parts of the cloud, but the stronger, clearer effect visible now is destruction of the nursery’s outer envelope while star formation continues inside. So Eta Carinae is not simply a creator or a destroyer. It is helping define the environment in which stars form, even as it steadily disperses the cloud that feeds them.

3 articles · Updated · Universe Today · Oct 29

Chandra and JWST observations showed a ghostly, isolated-looking cloud in the Carina Nebula is actively producing batches of hot, young stars rather than marking a dead stellar remnant.
X-ray and infrared data let astronomers map both the cloud’s structure and the stars forming inside it, adding detail to how the wider nebula continues to build massive new stars.
Ultraviolet radiation from nearby Eta Carinae and other hot young stars is simultaneously eroding the cloud, carving several comet-like knots known as cometary globules.
More than 7,500 light-years away, the Carina complex remains a key laboratory for stellar birth and death because Eta Carinae—a binary about 5 million times brighter than the Sun—is also expected to eventually explode as a supernova.